A light scattering and imaging optical system

ABSTRACT

An optical element for conveying scattered and image light to several detectors. The optical element may have the properties of a diffractive beam splitter and imaging lens. The detected light may be from an illuminated target. Further, there may be an optical element for conveying scattered light from a target via several zones to specific detectors, respectively. The latter optical element may include a multiple annular zone diffractive structure on a hybrid lens.

BACKGROUND

The invention pertains to optical arrangements, and particularly to those involving scattered light. More particularly, the invention pertains to collecting information from scattered light and images.

SUMMARY

The invention is an optical system for obtaining data from a region of interest with imaging and scattering detection and measurements of light.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an optical imaging channel for determining particle diameter and flow rate;

FIG. 2 is an optical scattering channel for determining particle type;

FIG. 3 is a combination optical imaging and scattering channel; and

FIG. 4 is an optical scattering device having a multiple zone diffractive structure.

DESCRIPTION

There may be system that collects both scattering and imaging information of an event such as in a cytometer flow channel and that of a cell, for example, a white or red blood cell. For instance, in cytometery, some of the goals may include a classification and counting of cell types along with a measurement of cell volume. An all optical approach to these goals may be achieved by measuring light scattered off of a cell at various angles along with imaging the cell to determine its diameter, and possibly other properties. The imaging and scattering may be accomplished with two independent optical systems, as illustrated in FIGS. 1 and 2, respectively. However, with the present approach, the scattering and imaging may be accomplished with one independent optical system, as illustrated in FIG. 3. The use of a diffractive or hybrid (i.e., diffractive-refractive) optical element may permit one to achieve an optical train that accomplishes both imaging and scattering.

FIG. 1 illustrates an optical imaging channel or train 10 that may be used for determining a diameter and flow rate, for example, of blood cells 12 (or other particles) in a flow channel 13. An imaging lens 14 may focus light 15 from a cell 12 on an imaging detector 16. Detector 16 may be an array of photodetectors or some other mechanism for image detection. Lens 14 and detector 16 may be aligned along an optical axis 17.

FIG. 2 illustrates an optical scattering channel or train 20 that may used for determining a type, and/or other property, of blood cell 12 (or other particle) in a flow channel 13. Light 18 scattered off of cell 12 may go through a lens 23 which may operate as a scatter collection lens. Scattered light 18 may be redirected by lens 23 which may proceed on to a detector 21. Detector 21 may be a photodetector or an array of photodetectors or some other mechanism. Detector 21 may be an annular-shaped detector. Detector 21 may detect FALS (forward angle scattering) and/or SALS (small angle scattering) of light. Detector 19 may be an extinction channel (unscattered by cell 12) for light that may be proceeding along optical axis 17.

FIG. 3 is a combination scattering and imaging channel or train 30 that may be used for determining a diameter, flow rate and/or type (and/or including possibly other properties) of blood cells 12 (or other particles 12) in the flow channel 13, or items in a region of interest. The particles 12 may be illuminated by a light source 44. Lens 24 may focus light 15 from a cell 12 on an imaging detector 22 with a double slit. Lens 24 may be regarded as a diffractive beam splitter channel. Light 15 may be of a plus first order imaging. Detector 22 may consist of an array of photodetectors or some other mechanism for image detection and as a scattering extinction channel. Lens 24 may collect scattered light 18 of a minus first diffracted order which may proceed on to detector 21. Detector 21 may be a photodetector or an array of photodetectors or some other mechanism. Detector 21 may be an annular-shaped detector. Detector 21 may detect FALS and/or SALS light. Detector 22 may be part of an extinction channel for light that may proceed along optical axis 17. Detectors 16, 19, 21 and 22 may also be regarded as a part of an imaging channel, an extinction channel, a FALS/SALS scattering channel and/or an imaging channel with a double slit, respectively. Signals from the detectors 21 and 22 may go to a processor 45 for analysis of signals and outputs of information about the target 12.

An angular scatter collection channel 40 (FIG. 4) may be implemented to collect efficiently and compactly angular zones 31, 32 and 33 of scattered light from a region of interest such as a flow channel 13 having cells 12 (or other particles) flowing in the channel. The region of interest or target may be illuminated by a light source 42. The flow channel 13 may be a part of a cytometer. Collected light may be redirected onto small detectors 35, 36 and 37 that are of similar area and close together. With a three angular zone diffractive surface structure on a hybrid lens 38, one may be able to collect annular zones 31, 32 and 33 of scattered light from the region of interest, and focus these different zones onto adjacent detectors 35, 36 and 37, respectively. By using the singular optical element 38 which combines both focusing and grating properties, a complete or nearly complete annular scattered region 31, 32, 33 may be captured and redirected onto a linear (or other configuration) detector array 35, 36, 37 in a compact module.

Each angular zone 31, 32 and 33, of the diffractive surface structure of optical element 38 may have an associated linear term (grating) that redirects captured scattered light over the respective region to a lateral position near an optical axis 39 of lens 38. Lens 38 may also serve to focus the captured scattered light. Each capture zone may be redirected by the diffractive structure on lens 38 in that particular zone to a different lateral position in a detector array plane 41 that may support, for instance, detectors 35, 36 and 37. The detectors may be of equal area, close together and/or compact with a maximum energy capture. Signals from detectors 35, 36 and 37 may go to a processor 43 for analyses of the signals, and an output of information about the targets 12. The light collection regions may include an extinction zone 31, a size zone 32 and a structure zone 33 which have scattered light directed to detectors 35, 36 and 37, respectively. Zone 33 may be the outermost zone from axis 39, as conveyed by the diffractive structure on lens 38. Zone 31 may be the intermost zone relative to axis 39, and zone 32 may be the intermediate zone between zones 31 and 33 relative to axis 39 of lens 38. There may instead be more or less than three zones in the angular scatter collection channel 40.

In the present specification, some of the matter may be of a hypothetical or prophetic nature although stated in another manner or tense.

Although the invention has been described with respect to at least one illustrative example, many variations and modifications will become apparent to those skilled in the art upon reading the present specification. It is therefore the intention that the appended claims be interpreted as broadly as possible in view of the prior art to include all such variations and modifications. 

1. An optical system comprising: an optical element having an imaging lens and diffractive beam splitter; an image light detector situated a first distance along an optical axis from the optical element; and a scattered light detector situated at a second distance from the optical element.
 2. The system of claim 1, wherein: the scattered light detector is a FALS and/or SALS scattering channel; and the image light detector is an imaging channel with a double slit.
 3. The system of claim 2, wherein the scattered light detector is for a diffractive order.
 4. The system of claim 3, wherein the image light detector is for another diffractive order.
 5. The system of claim 4, further comprising: a light source proximate to a target; and wherein: the scattered light detector may receive light scattered by the target; and the image light detector may receive light of an image of the target.
 6. The system of claim 5, further comprising a processor connected to the scattered light detector and the image light detector.
 7. A system for scattered light capture, comprising: a diffractive lens; and a detector array proximate to the diffractive lens.
 8. The system of claim 7, wherein the diffractive lens has a plurality of annular zones.
 9. The system of claim 8, wherein a diffractive structure is on the lens.
 10. The system of claim 9, wherein the lens comprises a hybrid lens.
 11. The system of claim 1 0, wherein the plurality of annular zones comprises an extinction zone, a size zone and a structure zone.
 12. The system of claim 11, wherein: the extinction zone is projected on a first detector of the detector array; the size zone is projected on a second detector of the detector array; and the structure zone is projected on a third detector of the detector array.
 13. The system of claim 11, wherein the plurality of annular zones conveys light scattered by a target.
 14. A method for detection comprising: providing an optical element; providing a detector array; directing scattered light with the optical element from a target to a first detector of the detector array; directing imaging light with the optical element from the target to a second detector of the detector array.
 15. The method of claim 14, wherein the optical element is a focusing lens having a diffracting structure.
 16. A method for detection comprising: providing an optical element; and directing scattered light with the optical element via a plurality of zones from a target to a plurality of detectors, respectively.
 17. The method of claim 16, wherein the optical element comprises a multiple zone diffractive structure on a lens.
 18. The method of claim 17, wherein the plurality of zones comprises: a first annular zone about an optical axis; a second annular zone outside of the first annular zone; and a third annular zone outside the second annular zone.
 19. The method of claim 18, wherein: scattered light via the first annular zone goes to a first detector of the plurality of detectors; scattered light via the second annular zone goes to a second detector of the plurality of detectors; and scattered light via the third annular zone goes to a third detector of the plurality of detectors.
 20. The method of claim 19, wherein: the first annular zone is an extinction zone; the second annular zone is a size zone; and the third annular zone is a structure zone.
 21. The method of claim 19, wherein the target may be a particle in a flow channel of an analyzer. 